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20 package org.apache.mina.util;
21
22 import java.util.Collection;
23 import java.util.Map;
24 import java.util.Set;
25 import java.util.concurrent.ConcurrentHashMap;
26 import java.util.concurrent.ConcurrentMap;
27
28 import org.apache.mina.core.buffer.IoBuffer;
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43 public class LazyInitializedCacheMap<K, V> implements Map<K, V> {
44 private ConcurrentMap<K, LazyInitializer<V>> cache;
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49
50 public class NoopInitializer extends LazyInitializer<V> {
51 private V value;
52
53 public NoopInitializer(V value) {
54 this.value = value;
55 }
56
57 public V init() {
58 return value;
59 }
60 }
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66 public LazyInitializedCacheMap() {
67 this.cache = new ConcurrentHashMap<K, LazyInitializer<V>>();
68 }
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76 public LazyInitializedCacheMap(final ConcurrentHashMap<K, LazyInitializer<V>> map) {
77 this.cache = map;
78 }
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83 public V get(Object key) {
84 LazyInitializer<V> c = cache.get(key);
85 if (c != null) {
86 return c.get();
87 }
88
89 return null;
90 }
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95 public V remove(Object key) {
96 LazyInitializer<V> c = cache.remove(key);
97 if (c != null) {
98 return c.get();
99 }
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101 return null;
102 }
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121 public V putIfAbsent(K key, LazyInitializer<V> value) {
122 LazyInitializer<V> v = cache.get(key);
123 if (v == null) {
124 v = cache.putIfAbsent(key, value);
125 if (v == null) {
126 return value.get();
127 }
128 }
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130 return v.get();
131 }
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136 public V put(K key, V value) {
137 LazyInitializer<V> c = cache.put(key, new NoopInitializer(value));
138 if (c != null) {
139 return c.get();
140 }
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142 return null;
143 }
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149 public boolean containsValue(Object value) {
150 throw new UnsupportedOperationException();
151 }
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157 public Collection<V> values() {
158 throw new UnsupportedOperationException();
159 }
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165 public Set<java.util.Map.Entry<K, V>> entrySet() {
166 throw new UnsupportedOperationException();
167 }
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172 public void putAll(Map<? extends K, ? extends V> m) {
173 for (Map.Entry<? extends K, ? extends V> e : m.entrySet()) {
174 cache.put(e.getKey(), new NoopInitializer(e.getValue()));
175 }
176 }
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181 public Collection<LazyInitializer<V>> getValues() {
182 return cache.values();
183 }
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188 public void clear() {
189 cache.clear();
190 }
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195 public boolean containsKey(Object key) {
196 return cache.containsKey(key);
197 }
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202 public boolean isEmpty() {
203 return cache.isEmpty();
204 }
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209 public Set<K> keySet() {
210 return cache.keySet();
211 }
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216 public int size() {
217 return cache.size();
218 }
219 }